Routing Ultraboard foam speeds and feeds smooth edge

[nolanola]

Hello.
I was in a grocery store and noticed that nice sign with a smooth edge (yellow, image attached).
I assume it's ultraboard.
We can not achieve that.
What bit and what speeds and feeds do you use?

Ultraboard website says:
Onsrud bit # 52-564 (2 flute, upcut, 1/4", 2-1/4", 1/4" feed rate 125” per minute run at 18,000 rpm)

We used a similar bit, and even after heavy priming and sanding the edges would be ugly (green, image attached).

Thank you.

 

[Superior_Adam]

That yellow sign does not look like UltraBoard Foam Substrate. It looks more like a PVC to me. On foam products we knife cut them on our Zund.

 

[AGCharlotte]

agree w/ Adam... that's not ultraboard, it's some sort of solid plastic.

 

[Sandman]

The yellow one looks exactly like expanded PVC like Celtec or Komatex.

 

[Grizzly]

I don't print a lot of Ultraboard but I do I print a lot of Gatorfoam. It is very prone to bit direction. Going one direction looks good while the other doesn't. Maybe you've already tried that and maybe Ultraboard foam doesn't react the same way but it's worth a shot.

 

[nolanola]

The yellow one looks exactly like expanded PVC like Celtec or Komatex.

Is it different from regular PVC (like Sintra or Ion).
Where do you order it from?

Thank you.

 

[Andy D]

I worked at a place a few years back that cut a lot of coro, foam board, gator board, sintra, even cardboard &
their router had a completely different head for every substrate... for example, the foam board was a vibrating straight edge blade.

 

[Pitzu]

Looks like high density extruded polystyrene...we cut it every day for letters. We usually use Datron - Triple flute end mill with toric cut for PU foam, using conventional milling.... and the finish is like the yellow letters. Even so, we don't consider it smooth edge. Hot wire cut is a lot smoother.
In foam board the core doesn't have high density as the extruded polystyrene and the edge ends up like the green letter. Oscillating knife might give a better finish.

 

[nolanola]

Looks like high density extruded polystyrene...we cut it every day for letters. We usually use Datron - Triple flute end mill with toric cut for PU foam, using conventional milling.... and the finish is like the yellow letters. Even so, we don't consider it smooth edge. Hot wire cut is a lot smoother.
In foam board the core doesn't have high density as the extruded polystyrene and the edge ends up like the green letter. Oscillating knife might give a better finish.

Great.
Who supplies high density extruded polystyrene?
What brands do you use?

 

[Emd2kick]

I worked at a place a few years back that cut a lot of coro, foam board, gator board, sintra, even cardboard &
their router had a completely different head for every substrate... for example, the foam board was a vibrating straight edge blade.

Andy, it's called an oscillating knife.

 

[Pitzu]

Great.
Who supplies high density extruded polystyrene?
What brands do you use?

I don't know if the brand we use (Apla XPS RF) is found in the US, but the most important is to be high density and have smooth faces, since you can also find models with rugged faces. It's widely used in construction for thermal insulation. We mostly use water based paint, since the solvent based paint will melt the foam.
High density polyurethane sheets should work also. I believe these could give you a better finish than extruded polystirene. You have to do some tests. These are also used in construction for thermal insulation.
For special applications there is Necuron: http://necumer.com/index.php/en/products/board-materials
In the US there is Corafoam https://www.dunagroup.com/usa/products/foams/corafoam-high-density

 

[The Sign Depot LLC]

As others have mentioned, the Claude sign looks more like expanded foam PVC with machines pretty well and it's much denser than Ultraboard so it will accept paint better. However, you can do it with Ultraboard if you're looking for something cheaper then PVC. For feeds and speeds, we use Belin 13317A which is a 1/8" single flute upcut spiral for plastic at 50ipm at 22,000 rpm. Its works beautifully.

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